Habit and leaf form.
Shrubs, or herbs, or arborescent;
laticiferous, or with coloured juice, or non-laticiferous and without coloured
juice. Normal plants. Perennial; with a basal
aggregation of leaves, or without conspicuous aggregations of leaves; often
cormous, or rhizomatous, or tuberous. Self supporting, or epiphytic, or climbing
(some very large); when climbing stem twiners, or root climbers, or scrambling.
Hydrophytic, or helophytic, or mesophytic; when hydrophytic rooted, or free
floating (Pistia). Leaves when hydrophytic, submerged, or emergent.
Heterophyllous (often entire/lobed compound), or not heterophyllous.
Leaves small to very large; alternate; spiral, or distichous;
petiolate (appearing conventionally petiolate when the sheath shed),
or sessile (Pistia only); sheathing (the sheath membranous, sometimes
deciduous). Leaf sheaths with free margins. Leaves normally
orientated (Acorus being excluded); simple, or compound.
Laminapinnately veined, or palmately veined, or parallel-veined;
cross-venulate, or without cross-venules; often cordate, or hastate, or
sagittate. Leaves ligulate, or eligulate. Axillary scales present, or absent.
Leaf developmentnot graminaceous; leavesoften becoming compound by necrosis.

General anatomy. Plants with
laticifers (articulated, branched or not), or without laticifers (e.g. some
Pothoideae, Pistia). Plants without silica bodies.

Reproductive type, pollination.
Plantshermaphrodite, or monoecious (then the males above),
or andromonoecious, or gynomonoecious, or gynodioecious, or
polygamomonoecious. Pollination anemophilous (rarely), or entomophilous;
mechanism conspicuously specialized (involving protogyny, combined with the
trapping of insects in the spathe, and their subsequent release), or
unspecialized.

Inflorescence, floral, fruit and seed
morphology. Flowers aggregated in inflorescences; in
spikes (very rarely shortly pedicellate  Pedicellarum). The
ultimate inflorescence units seemingly racemose. Inflorescences
scapiflorous (usually, more or less), or not scapiflorous; consisting of
specialised spikes (spadices) with spirals or rarely whorls of
flowers, variously pedunculate, sometimes tipped by a naked
appendix; usually conspicuously, often spectacularly
spatheate, or espatheate (in that there may be no true spathe in
Gymnostachys, Orontium). Flowersebracteate;
ebracteolate; small (numerous); (these or the spadix) often fragrant, or
malodorous; regular to very irregular; when irregular, asymmetric; 1–3
merous; cyclic. Perigone tube present (Spathiphyllum), or absent
(usually).

Perianthof tepals, or absent; 0, or 4, or
6, or 8 (rarely 12); free (usually), or joined; when present, 2
whorled (3+3 or 2+2); isomerous; when present, sepaloid;
similar in the two whorls (small, inconspicuous, often thick).

Androecium1 (e.g. Cryptocoryne), or 4, or 6, or
8(–12). Androecial members free of the perianth; free of one another,
or coherent; 1 whorled, or 2 whorled (commonly 3+3 or 2+2). Androecium
exclusively of fertile stamens. Stamens1–4, or 6, or
8–12; reduced in number relative to the adjacent perianth to isomerous
with the perianth to triplostemonous. Anthers basifixed;
non-versatile; dehiscing via pores, or dehiscing via short slits, or
dehiscing via longitudinal slits, or dehiscing transversely; extrorse;
bisporangiate, or tetrasporangiate. Endothecium developing fibrous thickenings.
The endothecial thickenings spiral. Anther epidermis persistent.
Microsporogenesis successive. The initial microspore tetrads tetrahedral, or
isobilateral, or decussate. Anther wall of the monocot type. Tapetum
amoeboid. Pollen shed in aggregates (occasionally), or shed as single grains;
when in aggregates, in tetrads (e.g. Caladium, Xanthosma). Pollen
grains aperturate, or nonaperturate; 1 aperturate, or 2–9 aperturate (?);
when aperturate, sulcate, or sulculate, or foraminate; 2-celled (10 genera), or
3-celled (7 genera).

Fruit fleshy (usually), or non-fleshy; an aggregate, or not an
aggregate. The fruiting carpel when monomerous, indehiscent;
drupaceous, or baccate, or nucular. Fruit indehiscent (usually),
or dehiscent; a capsule to capsular-indehiscent (occasionally), or a berry,
or a drupe, or a nut (occasionally). Capsuleswhen present,
splitting irregularly. Gynoecia of adjoining flowers combining to
form a multiple fruit (usually), or not forming a multiple fruit. The multiple
fruits coalescing (sometimes), or not coalescing. Dispersal unit the fruit, or
the inflorescence (the spadix sometimes forming a syncarp). Seeds endospermic,
or non-endospermic. Endosperm when present, oily (and starchy). Perisperm
absent. Seeds with starch. Cotyledons 1. Embryo chlorophyllous (6/6), or
achlorophyllous (Arisaema amurense); straight (linear). Testa without
phytomelan; membranous, leathery or crustaceous, but not black?.

General remarks. See the description
of Lemnaceae for a comment on the inappropriateness of incuding them
here.

Economic uses, etc. The family
furnishes numerous horticultural ornamentals, especially for indoors, and a few
are grown for food  e.g. Colocasia for taro, Monstera for
its fruits (Mexican breadfruit).

Look through the naked
bramble and black thorn And see the arum show its vivid green Glossy and
rich and some ink spotted like the morn Ing sky with clouds  in
sweetest neuks Ive been And seen the arum sprout its happy green
(John Clare c.1845, Look Through the Naked Bramble and Black
Thorn  Arum maculatum)

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